The present invention relates to automatic packaging, into blister packs, of various articles, such as tablets, pills, capsules and the like, in particular rhomboid and/or oblong.
In the described case, the present invention relates to a device for feeding articles to a blister band.
At present, pharmaceutical products are packaged into blister packs, formed by a strip formed with a series of blisters for containing articles.
The strip is usually closed by a sheet of e.g. aluminium, and the articles are withdrawn, according to known techniques, by breaking the aluminium sheet.
The blister packs are obtained by forming, in a suitable molding station, one or more rows of blisters in a continuous band of appropriate material, usually heat-formable or aluminium; afterwards the blister band passes through a filling station, where at least one article is introduced into each obtained blister; finally, the blister band is definitely closed by applying and welding an aluminium film on the surface thereof.
The filled and sealed blister band is cut into strips containing a predetermined number of blisters, therefore, articles, which define each a blister pack.
To fill the blisters of the blister band with articles, known machines are used, which operate according to different techniques.
A particularly widely used apparatus includes substantially a box-like container, which contains a bulk of articles and is situated directly over the blister band. The bottom of the container features an opening, whose width is not bigger than the width of the blister band.
The band is driven to translate with the empty blisters turned toward the container, so that the blisters pass gradually and longitudinally under the container.
The container, cooperating with spreading means, which are usually rotating and use brushes and similar elements, is fed by a suitable feeding channel which conveys the articles to be introduced, through the container, into the blisters. The quantity of the fed articles is such that they can accumulate on the surface of the blister band.
Consequently, the accumulated articles tend to enter the empty blisters and translate together with the belt, thus leaving the container.
A system like the one described above can be used with the belts moving in an intermittent or continuous way, and does not create the problem of the articles alignment with respect to the corresponding blisters.
Another known system for filling blisters includes a plurality of feeding channels, in which the articles are piled, and each channel is situated over a longitudinal row of blisters on the blister band.
The lower end of the feeding channels skims the surface of the band, and in phase relation with the band movement, the articles fall into the respective blisters, due to gravity, when they pass under the feeding channel.
The upper end of the channels is connected in a parallel way with a feeding hopper, which vibrates, and inside which the articles are contained in bulk.
Consequently, the vibrations of the hopper facilitate the orderly introduction of the articles in each feeding channel.
A further system for filling blisters includes a vibrating hopper, in which the articles are contained in bulk, and the bottom of which features suitable means for outputting the articles.
The shape of the output means is such that they direct the articles into substantially vertical feeding channels, in which the piled articles go down due to gravity until they enter the corresponding facing blisters of the blister band.
The output means usually include two rolls, mutually tangent and counter-rotating, so as to separate the articles contained in the vibrating hopper by pushing them upwards against their weight.
The rolls form relative circumferential grooves which define mouths allowing the articles to pass and to be conveyed to the relative feeding channels.
The speeds of the rolls can be different from one another, or any of the rolls can be kept motionless.
The output means can also include one roll mutually tangent to a lateral wall of the vibrating hopper.
According to a variant of the above system, it is possible to place a rotating cylinder between the blister band and the downstream end of the feeding channels.
The rotating cylinder features, on its outer surface, suitable recesses for receiving the articles let out by the feeding channels and positioning them into the blisters.
In this case, each recess is connected with a suction system, which allows to keep the article coming, due to gravity, from the feeding channels, and to a pressure system, which allows to eject the article and introduce it into the facing blister.
However, all the above described known systems have a series of problems due to the typical characteristics of the filling technique being used.
First of all, the articles, specially if very fragile, can be scratched or chipped by repeated pushes and reciprocal friction against the band surface, or against the walls of the container or the feeding channels, in other words, the articles can be damaged.
One of the main drawbacks derives from the fact that the blisters are wider than the articles and it happens quite often that a blister is filled with more than one article or not filled at all, because an article which has just entered the relative blister, can be thrown out during the blister band movement, thus leaving the blister empty.
The object of the present invention is to propose a device for feeding articles, especially tablets, pills and the like, in particular rhomboid and/or oblong articles, to a blister band situated below, which ensures perfect filling of each blister with one article, avoiding at the same time damages to the processed articles as well as to the blister band, all this independently from the shape and dimensions of the articles and relative blisters aimed at containing them.
Another object of the present invention is to propose a filling device which ensures high reliability and productivity in every working condition, without changing the functionality of the whole packing machine.
A further object of the present invention is to propose a device which allows to use any blister band, so as to make it possible to feed the blister bands with articles of different shapes or compositions, as well as to allow a particularly quick and easy packages output adjustment in relation to the packaging cycle characteristics.
Yet a further object of the present invention is to propose a device for feeding the articles, which can be used with any kind of blistering machine, and which is obtained by a simple, extremely practical and reliable, cheap technical solution, which ensures correct packaging of the relative articles into the corresponding blister bands.
The above mentioned objects are obtained, in accordance with the claims, by a device for feeding articles to a blister band moving longitudinally in a forward direction and having at least one row of blisters made therein for receiving corresponding articles, with said row of blisters being parallel to the direction, said device being characterized in that it includes:
at least one grid situated over said blister band, very close thereto, and featuring at least one longitudinal channel, matching with said longitudinal row of blisters, said articles being moved to said longitudinal channel;
a station for feeding said articles to said grid;
first oscillating means and second oscillating means for generating a relative motion between said grid and said blister band, so that said longitudinal row blisters is alternately partially closed and opened to facilitate stabile introduction of the articles in corresponding blisters present along said longitudinal channel.